Checking the function
Ensure that the vehicle is safely raised. Check that no objects are caught in the tire treads.
On vehicles with four-wheel-drive, the tests should be carried out with the vehicle raised so that all four wheels can rotate freely with attachments far out on the link arms so that the drive shafts are not damaged.
If the vehicle is equipped with TRACS or traction control (STC, DSTC) this function must be deactivated. Remove the fuse for the pump motor for the brake system in the relay/fusebox in the engine compartment. Note that this will store a diagnostic trouble code (DTC) in the brake control module (BCM). These diagnostic trouble codes (DTC) must be erased before delivery to the customer.
- Raise the vehicle so that the drive wheels hang freely.
- Start the engine and allow it to idle.
- Put the gear selector in position D so that the drive wheels start to rotate.NOTE:
Ensure that the wheels are not rotating when the gear selector is moved.
- Read off the gearbox output speed.
Read off the transmission input speed.
If the transmission input speed updates correctly it means that the fault was present previously but is not active now. There is an intermittent fault.
If the transmission input speed does not update correctly it means that the fault is permanent.
- Continue
Refer to Checking wiring and sensors